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Pin post for the community

The community owner can pin specific posts for all community members. Such posts will be returned at the top of the getPostsFeed and getCommunityPosts queries results when PINNED sort key is used. To pin the post for the community, pinPostForCommunity mutation should be executed. The mutation accepts only one required argument - postId. 
  mutation pinPostForCommunity {
    pinPostForCommunity(postId: 8) {
      response {
        isPinned
      }
      errors
    }
  }
The mutation returns a Post object. Detailed description and the full list of available properties can be found here.

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Unpin post for the community

A post that was previously pinned for the community, can be unpinned by the community owner. To do this, unpinPostForCommunity mutation should be executed. Similar to the previous mutation, it accepts only one required argument - postId. 
  mutation unpinPostForCommunity {
    unpinPostForCommunity(postId: 8) {
      response {
        isPinned
      }
      errors
    }
  }